Hypodermic syringe



Jan. 30, 1951 J. H. FRIDEN HYPODERMIC SYRINGE Filed June 3, 1949 FIG!INVENTOR JOHN H. FRIDEN 313%! AT TORNE Y.

Patented Jan. 30, 1951 HYPODERMIC SYRINGE John H. Friden, Maplewood, N.J., assignor to Bristol Laboratories, Inc., Syracuse, N. Y., a

corporation of New York Application June 3, 1949, Serial No. 97,027 7 2Claims. I

This invention relates to'hypodermic syringes, and in one of its morespecific aspects, to relatively small, compact syringes intended to beused once and then discarded.

It is a principal object of the invention to provide an improvedhypodermic syringe that is simple and compact in construction and iscapable of accomplishing its intended functions in an eflicient andtrouble-free manner.

Another object of the invention is to provide a single-use, disposablehypodermic syringe that is inexpensive in manufacturing cost.

Another object of the invention is to provide an instrument of thecharacter indicated, wherein a medicament-containing capsule of ampuleand a needle-carrying plunger are assembled in a condition ready for useat the time of manufacture, and wherein the operating needle and thecontents of the ampule are protected against in- Jury or contaminationduring the interval between the time of manufacture and use.

A further object of the invention is to provide a hypodermic needlehaving its parts so arranged as to visually indicate to the user, priorto injection of the medicament, whether the distal end of the needle,when inserted in the body of a patient, is in communication with a vein,or other blood vessel, or is positioned in body tissue.

To the end that the foregoing objects may be attained, the hypodermicsyringe of this invention preferably comprises a tubular body closed atits lower end and open at its upper end. The tubular body may be made ofglass or may be molded from a suitable plastic material that will notcontaminate the liquid medicament contained in the lower portion of thebody. A rupturable partition is disposed across the interior of thetubular body intermediate its ends and hermetically seals the medicamenttherewithin.

A reciprocable plunger is positioned in the portion of the tubular bodyabove the partition and is formed with coaxial, generally frusto-conicalend portions. Below the upper irusto-conical end portion is a suitablemeans, such as a pair of diametrically opposed wings, engageable by thefingers of the user, in the course of use of the instrument, to efiectmovement of the tubular body with respect to the plunger. The plunger,preferably made of a suitable plastic, is formed with an annular recessabove the lower frustoconical end portion, and is provided with aresilient distortable sealing ring that registers with the annularrecess and is in intimate contact with the interior of the tubular body.The sealing ring is, in turn, provided with one or more external annulargrooves.

A hypodermic needle, pointed at each end, is coaxial with thefrusto-conical portions of the plunger and extends beyond each end ofthe plunger. The needle is secured to and is movable with the plunger.

A generally conical cap, likewise preferably made of a suitable plasticmaterial and having a series of angularly spaced external stiffeningribs, covers the portion of the needle that extends above the plungerand frictionally engages the upper frusto-conical portion of theplunger. cap is so arranged with respect to the plunger as to bemaintained in spaced relation to the upper portion of the needle.

The above enumerated objects, as well as other objects, together withthe advantages of the invention, will be readily comprehended by personsskilled in the art upon reference to the following detailed description,taken in conjunction with the annexed drawing, which respectivelydescribe and illustrate a preferred form of hypodermic syringeconstructed in accordance with the invention.

In the drawing:

Figure l is a view in elevation of a hypodermic syringe embodying theinvention, the protective cap of the complete instrument being shown ina position removed from the plunger;

Figure 2 is an enlarged central vertical crosssectional view of theinstrument shown in Figure l with the parts in assembled position;

Figure 3 is a view taken along line 3-3 of Figure 2; and

Figure 4 is a view taken along line 4-4 of Figure 2.

Referring now to the drawing, wherein like reference numerals denotecorresponding parts throughout the several views, the hypodermic syringeof this invention includes a first unit or ampule ID that comprises aright cylindrical tubular body 12 closed at its lower end I4 andpreferably formed of a suitable transparent plastic material that willnot contaminate or adversely affect liquid medicament l6 containedtherein. A rupturable partition 18, made of rubber, plastic or the like,is disposed across the interior of tubular body I2 and hermeticallyseals the medicament therewithin.

A second unit 20, reciprocable in tubular body 12, includes a plunger22, preferably made of a suitable plastic material. Plunger 22 comprisesan upwardly tapering frusto-conical upper end portion 24, a pair ofdiametrically opposed lateral wings or extensions 26, and a downwardlytapering frusto-conical lower end portion 30 that is coaxial withfrusto-conical upper end portion 24.

The diameter of the plunger is slightly smaller than the internaldiameter of tubular body l2 to eliminate undue friction. The plunger isformed with an annular recess 32 above irusto-conical lower portion 30.The annular recess is adapted to receive and retain a sealing ring 34made of a suitable distortable resilient material, such as rubber. Ring34 is provided with a plurality of external annular grooves asintermediate its ends. The major diameter of lower frusto-conicalportion 30 is substantially less than the internal diameter of thetubular body to facilitate slipping sealing ring 34 on the plunger andinserting the plunger and sealing ring into the tubular body.

Embedded in plunger 22 and movable therewith is a hypodermic needle 40that is coaxial with frusto-conical portions 24 and 30. As is best shownin Figure 2, the ends of the needle extend beyond the corresponding endsof the plunger; also, the needle is pointed at its ends, as indicated at42 and 44. When the parts are in the relative 1 position shown in Figure2, lower end 44 of the needle is positioned in spaced relation to theupper surface of partition I8.

The portion of the needle that extends above the plunger is protectedagainst damage or contamination when the instrument is not in use by agenerally conical cap 46, having a lateral external flange 48 at itsopen end. The protective cap frictionally engages the portion of theplunger above the wings and bears against the upper surface of wings 26,whereby the cap is maintained in the position shown in Figure 2 withrespect to the plunger. The cap includes a plurality of angularly spacedlongitudinal external ribs 50, as is shown in Figures 1 and 2. Ribs 50serve to lend rigidity to the cap proper and its flange 48.

The parts are sterilized and assembled, as shown in Figure 2, at thetime of manufacture. With the parts so arranged, ring 34 not onlyprovides an eflective seal to prevent entry of dust or other foreignmaterial which might contaminate the contents of the tubular body, butalso frictionally maintains plunger 22 in the illustrated position withrespect to the tubular body so that lower needle point 44 is spacedabove partition l8.

The hypodermic syringe of this invention is used in a. manner that willnow be briefly described. Cap 46 is removed from plunger 22 and the usergrips the syringe, placing his index and middle fingers on correspondingwings 26, and his thumb against closed end 14 of the tubular body.Exposed point 42 of the needle is inserted in the patients body. Theuser may readily determine whether end 42 of the needle is properlypositioned in the patient by moving ampule l0 downwardly a shortdistance with respect to plunger 22, as viewed in Figure 1. If point "42of the needle communicates with a. vein or other blood vessel, bloodwill be drawn into the needle and appear in the space above partitionl8. If the injection is to be intramuscular, the user withdraws theneedle and moves the plunger back to the position shown in Figures 1 and2, thereby ejecting the blood remaining in the needle. The needle isreintroduced into the body and the described procedure is repeated untilno appreciable amount of blood appears.

After the needle has been inserted into the desired location, ampule I0is moved by thumb pressure along piston 22 so that lower end 44 of theneedle pierces partition i8 and the liquid medica-' ment "3 istransmitted through the needle into the patients body. Ampule in may bemoved upwardly along plunger 22 until the upper extremity of tubularbody [2 bears against the under surface of wings 26, whereby furtherupward movement of the ampule with respect to the plunger is arrested.

From the foregoing, it is believed that the construction, operation andadvantages of my present invention will be readily comprehended bypersons skilled in the art. It is to be clearly understood, however,that various changes in the apparatus set forth above may be madewithout departing from the scope of the invention as defined in theclaims of this application, it being intended that all matter containedin the description or shown in the drawing shall be interpreted asillustrative only and not in a limiting sense.

I claim:

1. A hypodermic syringe comprising a tubular body closed at its lowerend and open at its upper end and containing liquid to be dispensedtherefrom, a rupturable partition across the interior of the tubularbody intermediate its ends and hermetically sealing the liquidtherewithin, a reciprccable plunger in the upper end of the body. saidplunger comprising generally frusto-conical upper and lower end portionsand laterally extending finger engageable means below the frustoconicalupper end portion, said plunger having an annular recess between theflange and the frustoconical lower end portion, a resilient distortablesealing ring positioned in the annular recess and in intimate contactwith the inner surface of the tubular body, a double-pointed hypodermicneedle secured to and movable with the plunger, said needle beingcoaxial with the frusto-conical portions and extending beyond each endof the plunger, and a protective cap covering and spaced from theportion of the needle that extends beyond the upper end of the plunger,said cap frictionally engaging the upper portion of the plunger andbearing against said means.

2. A hypodermic syringe as defined in claim 1, wherein the meanscomprises oppositely disposed extensions having coplanar upper surfacesand the protective cap comprises a generally conical tubular memberhaving an external lateral flange at its open end and a plurality ofangularly spaced longitudinal external ribs integral with the flange andthe tubular member.

. JOHN H. FRIDEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 159,192 Leiter Jan. 26, 1875446,125 Schirmer Feb. 10, 1891 791,802 DeLisle June 6, 1905 1,100,798Wedig June 23, 1914 1,179,561 Reed Apr. 18, 1916 1,817,003 Hein Aug. 4,1931

